Solid ink or phase change ink printers conventionally receive ink in a solid form, either as pellets or as ink sticks. The solid ink pellets or ink sticks are placed in a feed chute and delivered to a heater assembly. Delivery of the solid ink may be accomplished using gravity or an electromechanical or mechanical mechanism or a combination of these methods. At the heater assembly, a heater plate melts the solid ink impinging on the plate into a liquid that is collected and conveyed to a print head for jetting onto a recording medium.
In known printing systems having an intermediate imaging member, the print process includes an imaging phase, a transfer phase, and an overhead phase. In ink printing systems, the imaging phase is the portion of the print process in which the ink is expelled through the piezoelectric elements comprising the print head in an image pattern onto the print drum or other intermediate imaging member. The transfer or transfer phase is the portion of the print process in which the ink image on the imaging member is transferred to the recording medium. The image transfer typically occurs by bringing a transfer roller into contact with the image member to form a transfer nip. A recording medium arrives at the nip as the imaging member rotates the image through the transfer nip. The pressure in the nip helps transfer the malleable image inks from the imaging member to the recording medium. When the image area of an image recording substrate has passed through the transfer nip, the overhead phase begins. The transfer roller may be immediately retracted from the imaging member as the trailing edge of the substrate passes through the nip, or it may continue to roll against the imaging member at a reduced force and then be retracted. The transfer roller and/or intermediate imaging member may be, but is not necessarily, heated to facilitate transfer of the image. In some printers, the transfer roller is called a fusing roller. For simplicity, the term “transfer roller” as used herein generally refers to all heated or unheated rollers used to facilitate transfer of an image to a recording media sheet or fusing the image to a sheet.
Many printers have multiple trays in which different types of recording media are stored. These different media may be different sizes of paper or polymer film recording media. These various media also have different thicknesses. As these various media are retrieved from their source trays, transported through the printer, passed through the transfer nip, and dropped into the output tray, they affect printing process parameters. The process parameters affected by different media thicknesses include transfer load, imaging member velocity during the transfer phase, imaging member temperature, and media pre-heater temperature, for example. In some printers, the operator is required to provide media thickness information through a user interface. Operator entry of parameters is subject to a risk of error and also burdens the operator with another aspect of printer management. To reduce requirements for operator interaction, some printers require the operator to select a thick or thin media mode of operation. While this type of operator interaction is an improvement, it still requires a subjective determination from the operator as to whether the thick or thin mode is optimal and does not enable more exact printing process parameter adjustments to be made.